In high sea states (greater than 4 on the Beaufort scale), boats and ships must negotiate a variety of extreme conditions. Excessive rolls, yaws, and pitches, coupled with taking on water make working and living on a ship hazardous. Seakeeping (defined as the ability of a vessel to navigate safely at sea for prolonged periods during stormy weather) limits advanced, high speed, vessels from providing an overall effective platform for many open-water applications—including ferrying, search and rescue operations, and military missions. In high seas, most ships must sacrifice either speed or seakeeping ability, and neither can be achieved without size. To survive in high sea states and maintain speed, conventional displacement ships must be large. The relationship between a ship's maximum speed and its hull length is called “hull speed.” Consequently, small, conventional displacement ships are unable to perform high-speed missions in rough seas.
Existing ships often incorporate passive stability systems such as bilge keels, outriggers, anti-roll tanks, and paravanes to reduce the tipping of ships. Active stability systems include the use of stabilizer fins attached to the side of the vessel to counteract unwanted motion of the vessel. Active fin stabilizers are often used to reduce the roll a vessel experiences. There is currently no way to stabilize a ship, and the present solutions are limited to use in countering the small motions of waves.
Thus, there is a need for a dynamic stability system that can assess and counteract a variety of factors that adversely affect ship stability, to provide ships with enhanced ability to perform at extreme sea states.